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Science: one of the army of our country

⚔️🔬 Science 🔬⚔️         The importance of science is well known today. Science is not just limited branch, it is very wide branch and extend study of the basics of science makes a new branch of science. For example, Biology is branch in which the study of living being occurred,  Chemistry the study of chemical, Microbiology the study of microorganisms, cell biology the study of all types of cell....etc....etc. But science does not seem to be as important as it should be. Now people understand that there is no alternative without science. Every one know that the science is a great career field, this is also a good education field, that's all there is to it. Still, we can say that ' Science is the one of the army of our country '. What is this nonsense....... How is that........ So let to prove this sentence, with evidence.... At first I would like to say that, we can't imagine the world without Science, because Science has given us so much
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Photoelectric effects

💫PHOTOELECTRIC EFFECTS 💫


*Photoelectric Effect Definition÷ 

The phenomenon of emission of electrons by certain substance , when it is exposed to radiations of suitable frequency is called as "Photoelectric effect"

"Photoelectric effect was discovered by Heinrich Rudolf Hertz in 1887" .

  

*Experimental study of Photoelectric Effect÷

  • Aim : To verify the phenomenon of photoelectric effects. 

  • Photoelectric effect apparatus : Evacuated glass tube having Quartz window, photo sensitive plate, metal plate, voltmeter, microammeter, commutator, battery.

  • Photoelectric effect experimental setup {arrangement}:

Photoelectric effect experimental setup

  • Observation :  the Hertz experimental arrangement of photoelectric effect is shown in over above. Setup the apparatus complete the circuit as similar to the diagram .It consists of an evacuated tube having photosensitive plate 'C' and another metal plate 'A' .Monochromatic light from the source 'S' of sufficient short wavelength enters the tube through quartz window 'W' .The electrons are emitted by the plate C (emitter) and collected by the plate A (collector),the electric field created by the battery. When light is incident on the emitter plate the photo electrons are emitted. The photo electrons are attracted by positive plate A .The emissions of electrons cause flow of electrons and we know the flow of electrons means electric current start in the circuit.the potential difference between the emitter and collector plate is measured by voltmeter and the flow of current measured by microammeter. 

Conclusion : If the setup placed in sun light the photo electric current start when the minimum frequency of radiation incident on emitter. 
     The number of photoelectron emitted per second is directly proportional to the intensity of light. 
   The emission of photoelectrons is an instantaneous process.

        "The minimum frequency of incident radiation for which photoelectrons are just emitted from photosensitive material is called Threshold Frequency." 



*Photoelectric effect conditions :

     The photoelectric effect occurs when light incident on a photosensitive metal .
       The frequency of light greater the the Threshold frequency if and only if photoelectric effect are possible .
  The emission of photoelectrons is an instantaneous process.if stop the light ,stop the current in circuit.









*Science world*
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